Sharp wide open across the frame, fast and accurate focus, solid build

Cons:

CA wide open, no weather seal

The 24-105L was my most used lens for two years but I have hardly touched it since I got the 35L three months ago. Not surprisingly this lens is sharp in the center wide open, but surprisingly sharpness is uniform across the frame except extreme borders. This alone makes it stand out among fast wide angle lenses, excelling over a new design like the Sigma 30, even 10 years after first release. Focus is fast, silent, and sure. The 35L has a great feel: smooth focus ring, solid construction, great proportion on a medium-sized SLR, and beautiful front element. Drawbacks include CA wide open, lack of weather seal, and 'plastic' finish compared to, say, the 135L. The 135L may be my best built, best performing lens, but the 35L is by far the most fun.